Lubricant for rolling metals



United States Patent O 3,311,557 LUBRKCANT FOR ROLLING METALS Knapcl F.Schiermeier and Clark W. Judd, Alton, 11]., assiguors to Shell OilCompany, New York, N.Y., a corporation of Delaware No Drawing. FiledNov. 30, 1964, Ser. No. 414,869 12 Claims. (Cl. 25234) This applicationis a continuation-in-part of application Serial No. 309,297, filed Sept.16, 1963, now abandoned.

This invention relates to improved lubricants, more particularly, itrelates to aqueous base lubricants designed especially for use in hotrolling non-ferrous metals, such as aluminum.

It is well known from the prior art that non-soluble oils such asstraight mineral oils or their emulsions are unsatisfactory aslubricants for the hot rolling of nonferrous metals such as aluminum.Straight mineral oils or composite mineral oils lack the requiredcooling properties since the temperature encountered during the hotrolling of aluminum is in the range of from about 300 F. to about 900 F.To take advantage of the lubricating qualities of oils, emulsions havebeen tried for this purpose. Emulsions are generally prepared by mixinga soluble oil with a large proportion of water, for example, from 10 to50 parts of water per part of oil. Conventional soluble oils for hotrolling aluminum are generally composed of light viscosity mineral oil,petroleum sulfonates, resin soaps or soaps derived from fatty acids,coupling agents, wetting-out agents, and a small proportion of water inneat oil. Although emulsions are good coolants, they have a disadvantagein that they cause staining of the worked surfaces and also causeso-called metal pickup. This phenomenon is the appearance of nodules oraccretions of metal on the surfaces of the rolls. ,The accretions buildup, causing sticking and deformation, which at times become seriousenough to cause shutdown and require regrinding of the rolls. Inaddition to the loss of time and money, spoilage and waste of metal arethe results of improper lubrication.

It has now been discovered that a soluble oil for compositing with waterand which results in an excellent lubricant for the hot rolling ofnon-ferrous metals such as aluminum is provided by a mineral lubricatingoil containing an additive combination comprising a minor amount of eachof an alkanolamine soap of a fatty acid, free fatty acid, and analkylene polyol. The concentration of each additive in the soluble oilis critical for achieving excellent performance of the final compositionin providing good cooling and lubricating properties, bright surfacefinish, and resistance to staining and metal pick-up.

The mineral oil used as the base for the soluble oil should be a HVIlubricating oil, i.e. one having the viscosity index (Dean-Davis) of atleast 80, preferably 90- 100. Mineral oil fractions of this type arederived from paraffinic, naphthenic or mixed base crudes. Viscosity asdetermined at 100 F. is in the range from about 75 to 250 SUS,preferably between 100 and 150. A typical mineral base of this kind is ahigh viscosity index refined mineral lubricating oil having thefollowing properties:

GR, API, 60 C. 32.2 Color, ASTM 1 Pour point, F. Q. 5 Flash, F. COC 370Fire, F. 435 Viscosity, SUS at 100 F. 103 Viscosity index 93Neutralization number 0.01

Patented Mar. 28, 1967 The low viscosity index oils (10-50 VI) aregenerally unsuitable for use as the mineral oil base for the solubleoils of the present invention.

The fatty acid used in the present composition includes fatty acids offrom 12 to 30, preferably 14 to 18 carbon atoms and may be derived fromanimal, vegetable or mineral sources, such as fatty acid obtained fromcotton seed oil, soy bean oil, coconut oil, corn oil, palm oil, lardoil, tallow and pure saturated and unsaturated fatty acids, such asstearic, oleic or linoleic acids. Oleic acid or mixed fatty acids havinga high proportion of oleic acid are particularly suitable because of lowmelting point. A suitable fatty acid is sold by Emery Industries underthe trade name of Emery 3305, the major constituents and approximateamount being oleic acid (45% wt.), stearic acid (15% wt.), linoleic acid(15% wt.), and palmetic acid (15% wt.). A particularly suitable fattyacid is Emery 3252 which is of low melting point and results in an oilblend of low pour point. The amount of fatty acid used in the solubleoil is from about 10% to about by weight and preferably from about 15%to 25% by weight.

Of the akanolamines, the lower alkanolamines, such as the ethanolamines,are suitable. Such alkanolamines react readily with the fatty acid.Excellent results are obtained with diethanolamine, which is relativelyinexpensive and readily available. Only sulficient alkanolamine is usedto react with a portion of the fatty acid so as to leave a relativelylarge amount of free fatty acid in the soluble oil, e.g., sufiicientalkanolamine is used to react with on the order of from about 15-40% ofthe fatty acid. The amount of the alkanolamine is controlled so that theratio of the total base neutralization number-electrometric (T BN E asdetermined by the ASTM 664 method) to the total acid neutralizationnumber-electrometric (TAN-E as determined by the ASTM 664 method) of thesoluble oil is in the range from about 0.15 to 0.4 and preferably from0.15 to 0.3. When this ratio is too low, emulsions of the soluble oilwith water may have poor stability. At high ratios, pick-up of aluminumfines by the emulsions may become excessive.

Alkylene polyols suitable for use in the composition of the inventionare those wherein the alkylene group has from 4-8 carbon atoms.Particularly suitable and preferred alkylene polyols are the diols, suchas hexylene glycol, 1,2-hexane diol, 1,5-pentane diol, 1,5-hexane dioland the like. From about 2 to 8% by weight of the alkylene polyol isused in the soluble oil.

Other additives can be added to compositions of this invention in orderto improve their performance. For example, emulsious containing fattyacids are susceptible to deterioration, especially when used at elevatedtemperatures for long periods of time. Such emulsions develop anextremely strong, foul and undesirable odor which renders themobjectionable. It is generally desirable to add a small amount of agermicidal agent to inhibit bacterial growth and fermentation. Formalin(aqueous solution of approximately 40% formaldehyde) and phenoliccompounds, e.g. phenol, chlorophenols such as tetrachlorophenol, phenylphenols such as o-phenyl phenol, and the like are well known germicidalagents. The phenolic germicidal agents are preferred and are availablecommercially. The amount of germicidal agent used generally does notexceed 5% by weight, usually from (ll-1% by weight added to the solubleoil is very effective. Minor amounts, e.g., 0.11% by weight ofantitoxidants can be used. A highly suitable antioxidant is2,6-ditertiary butyl-4-methyl phenol.

Illustrative examples of soluble oils of this invention comprise:

Composition A- Percent Weight Germicidal agent (0.25% wt. Dowicide C.O.

+0.25% wt. Dowicide 6) 0.5

Composition D- Emery 3305 fatty acid 18.0 Diethanolamine 2.3 1,5-pentanediol 3.9 Mineral lubricating oil (same as A) 75.8

Composition E- Emery 3252 fatty acid 25.0 Diethanolamine 1.5 Hexyleneglycol 7.5 Mineral lubricating oil (same as A) 66.0

Plus 0.5% by Weight 2,6-ditertiary butyl-4- methyl phenol and 50 p.p.m.by weight Dow Corning Antifoam A.

In preparing the soluble oil, the fatty acid and a portion of the glycolare mixed and heated to about 170 F. The ethanolamine is added and thetemperature is increased to about 180 F. which is maintained for about 1/2 hours to react the fatty acid and the ethanolamine. The reactionmixture is blended with the oil at about 100120 F., followed by theaddition of additives such as antioxidants, antifoam agents and thelike. The remainder of the glycol is added and mixed for about /2 hour.Mechanical agitation is used for mixing.

sions form quite readily, which is an important factor since the mixingof the oil and water is done in the field by means such as airagitation, propeller mixing and the like. The composition of theemulsion yields a proper balance among the forces of attractionoperating between the oil and Water phase, the oil phase and the metal,and the water phase and the metal. The composition of the emulsion issuch that an oil-in-water emulsion and a Water-in-oil emulsion arealmost equally likely to form spontaneously, yet the resulting emulsionis quite stable. To illustrate the properties of the composition of thepresent invention, a comparison is made with a soluble oil comprising:

Percent Weight Mineral lubricating oil (VI 94, 105 SUS 100 F.) 62.9

*The soluble oil base is: Percent weight soidiunilnsulfonates (40% wt.sodium sulfonutes n o Hexylene glycol 3.0 Triethanolamine 2.3 Oleic acid1.6 Water 6.8

Properties of Composition A and Composition E of the invention and thecomparative oil is given in Table I.

TABLE I Composition Composition Compara- A E E tive Oil 1 i Gravity, API29. 5 29. 4 f 20. 0 Four Points, 35 10 -15 Flash, 000, F 265 235 30aViscosity at 100 F., SUS-.. 134 113 750 Initial p 7. 9 7. 7 TEN-132..--9.2 7.4 25.0 TAN-E 25. 5 44. 3 22. 0 Ratio TBN-E/TAN-E 0. 36 0. l7 1. 14Saponification No., mg.

KOH!g 29. 2 46. 0 Ash 0. 01 0. 002 1. 33 Water, percent wt Trace 0. 6

Emulsion stability is indicated by preparing an emulsion of oil (6% v.)and distilled Water and measuring separation of oil and water from a 100cc. sample at the end of four hours. Affinity of the oil for metal isdemonstrated by a test wherein aluminum fines (95% thru 200 mesh, 80 to90% thru 325 mesh) are mixed (0.1% wt. of emulsion) at room temperaturewith an emulsion of oil (6% v.) and distilled water and the separationrate of the fines is determined by sampling the emulsion, filtering thesample, and weighing the amount of aluminum recovered from the sample.Comparative results from these tests are given in Table II forComposition A and the comparative oil.

TABLE II Aluminum suspended, percent I oi Emulsion Emulsion Stabilityseperation in 4 hours Aluminum Sediment on bottom 1 Includes approx.0.060% w. zinc soaks.

Finished emulsions are prepared by admixing, on a volume basis, fromabout 2% to about 10%, preferably about 3% to 6% soluble oil with Water.In general, the present soluble oils can be used in concentrations lowerthan those used with conventional soluble oils From the resultspresented in Table II, it can be seen that the emulsion prepared fromComposition A of the present invention is more stable and markedlysuperior with respect to metal pickup than that from the comparawhich isadvantageous from a cost standpoint. The emultive oil composed ofconventional soluble oil additives.

EXAMPLE I emulsion.

EXAMPLE II Composition E was similarly used in concentrations rangingfrom about 2.5% to 5% by volume oil with excellent results. Quality ofrolled strip was quite good even for high magnesium content alloys suchas 5052 and 5252. After three weeks of operation, about -20% by volumeof the emulsion was withdrawn each week and replaced with fresh emulsionto extend service life. Ash content due to build-up of aluminum finessuspended in the emulsion was 0.030% to 0.040% by weight. In contrast,ash content of a commercial soluble oil (typical properties are a ratioTBN-E/TAN-E of 0.57, saponification No. 26.9, and 25.8 API gravity)reaches about 0.120% in 3-4 weeks and is discarded. The pH of theemulsion is relatively constant at about 7 which shows good resistanceto air oxidation. Bacteria count is quite low at about 2 million whichis in marked contrast to the 100-200 million often obtained with thecommercial soluble oil. A commercial germ-icide (Tris Nitro sold byCommercial Solvents Company) of 0.01% by weight is maintained in therolling oil. Low emulsion concentrations are used and excellent emulsionstability is obtained, compared with commercial oil. Thus, superiorperformance of the soluble oil of the present invention compared withthe commercial oil commonly used is demonstrated.

We claim as our invention:

1. A soluble oil suitable for use in hot rolling non-ferrous metalswhich consists essentially of a major amount of a mineral lubricatingoil having a viscosity index of at least 80 and a viscosity at 100 F. offrom about 75 to about 250 SUS, from about 10% to about 30% by weight offatty acid having from 12 to 30 carbon atoms, from about 2.0% to about8.0% by weight of an alkylene polyol wherein the alkylene group has from4 to 8 carbon atoms, and an ethanolamine in an amount to provide a ratioof the total base numberelectrometric to total acid numberelectrometricin the range from about 0.15 to *2. A soluble oil suitable for use inhot rolling non-ferrous metals which consists essentially of a majoramount of a mineral lubricating oil having a viscosity index of at least80 and a viscosity at 100 F. in the range from about 100 to about 150SUS, from about 10% to 30% by weight of a fatty acid having from 14 to18 carbon atoms, from about 2.0% to about 8.0% by weight of an alkylenediol having from 4 to 8 carbon atoms, and an ethanolamine in an amountto provide a ratio of the total base number-electrometric to total acidnumber-electrometric in the range from about 0.15 to 0.3.

3. The soluble oil of claim 2 containing from about 0.1% to 1% by weightof 2,6-ditertiary butyl-4-methyl phenol.

'4. A soluble oil suitable for use in hot rolling aluminum whichconsists essentially of a major amount of a mineral lubricating oilhaving a viscosity index of at least 80 and a viscosity at 100 F. in therange from about to 250 SUS, from about 10% to 30% by weight of a fattyacid having from 14 to 18 carbon atoms, from about 2.0 to 8.0% by weightof an alkylene diol having from 4-8 carbon atoms, and diethanolamine inan amount to provide a ratio of the total base numberelectrometric tototal acid numberelectrometric in the range from about 0.15 to 0.4.

5. The soluble oil according to claim 4 wherein the alkylene diol ishexylene glycol.

'6. A soluble oil suitable for use in hot rolling aluminum whichcomprises a major amount of a mineral lubricating oil having a viscosityindex of at least and a viscosity at F. of from about 100 to about SUS,about 25% by weight of a fatty acid having from 14 to 18 carbon atoms,about 7.5% weight hexylene glycol, and about 1.5% by weightdiethanolamine.

7. An aluminum hot rolling lubricant composition comprising a majoramount of water and from about 2% to 10% by volume of the soluble oil ofclaim 1.

8. An aluminum hot rolling lubricant composition comprising a majoramount of water and from about 2% to 10% by volume of the soluble oil ofclaim 2.

9. An aluminum hot rolling lubricant composition comprising a majoramount of water and from about 2% to 10% by volume of the soluble oil ofclaim 3.

10. An aluminum hot rolling lubricant composition comprising a majoramount of Water and from about 2% to 10% by volume of the soluble oil ofclaim 4.

11. An aluminum hot rolling lubricant composition comprising a majoramount of water and from about 2% to 10% by volume of the soluble oil ofclaim 5.

:12. An aluminum hot rolling lubricant composition comprising a majoramount of water and from about 2% to 10% by volume of the soluble oil ofclaim 6.

References Cited by the Examiner UNITED STATES PATENTS 2,846,393 8/1958Cook et al. 25249.5 X 2,913,411 11/ 1959 Schiermeier 252-495 X 2,981,1284/ 196 1 Flemming 252-49.5 X 3,071,544 1/1963 Rue 25249.5 X

FOREIGN PATENTS 241,332 11/1962 Australia.

DANIEL E. WYMAN, Primary Examiner.

- C. F. DEES, Assistant Examiner.

1. A SOLUBLE OIL SUITABLE FOR USE IN HOT ROLLING NON-FERROUS METALSWHICH CONSISTS ESSENTIALLY OF A MAJOR AMOUNT OF A MINERAL LUBRICATINGOIL HAVING A VISCOSITY INDEX OF AT LEAST 80 AND A VISCOSITY AT 100 F. OFFROM ABOUT 75 TO ABOUT 250 SUS, FROM ABOUT 10% TO ABOUT 30% BY WEIGHT OFFATTY ACID HAVING FROM 12 TO 30 CARBON ATOMS, FROM ABOUT 2.0% TO ABOUT8.0% BY WEIGHT OF AN ALKYLENE POLYOL WHEREIN THE ALKYLENE GROUP HAS FROM4 TO 8 CARBON ATOMS, AND AN ETHANOLAMINE IN AN AMOUNT TO PROVIDE A RATIOOF THE TOTAL BASE NUMBER-ELECTROMETRIC TO TOTAL ACIDNUMBER-ELECTROMETRIC IN THE RANGE FROM ABOUT 0.15 TO 0.4.